Wednesday, January 31, 2007

Reader mail

It's a slow news day here (unless you want to read about how I spent hours yesterday copying numbers from one file to another, and I sincerely doubt you do), so let's dip into the ever-burgeoning mailbag for a question. It was sent in early January by "super nova" (and appears slightly edited here): The Solar System was formed from a solar nebula, which occurred after a star expanded into a red giant. Does this mean that if Earth was formed this way, and living beings were created this way, the very same conditions should be taking place in other galaxies, meaning that there may be other life forms in other galaxies?

First, let me correct one small factual error in the first sentence. The Solar System indeed formed from a nebula, probably one much like the Orion Nebula. But this nebula did not come (directly) from a red giant star. The Milky Way Galaxy is pretty efficient at recycling matter. When stars finish their lives, they often have only used less than 50% of their hydrogen, the main fuel for stars. Bigger stars are less efficient, perhaps only using 10% (or less!) of their fuel, while more efficient models like the sun use over half of their fuel. When a star dies, whether by a supernova explosion or by a red giant star puffing up into a planetary nebula, all the unused hydrogen is returned to the Milky Way Galaxy, but this gas is far too hot to make new stars right away. Our galaxy mixes the gas up with cooler gas, and the hot gas radiates away heat to cool, and eventually it gets down to the temperature of most of the other gas in the galaxy.

By a method we don't understand, this gas sometimes gets collected into large, dense blobs called "molecular clouds." Molecular clouds can only be seen with radio waves, and they are like giant refrigerators -- the temperature of the gas inside is only a about 10 or 20 degrees above absolute zero (-273 degrees Celsius, or -460 degrees Fahrenheit)! When the gas is this cold, gravity begins to draw it close together to make dense clumps; these dense clumps form new stars. And it is from such a clump that our sun was born.

Our reader is right to guess that this process is happening everywhere. We see thousands upon thousands of stars being born across our galaxy. On average, we probably get one or two new stars every year in the Milky Way! We also see this same process happening in other galaxies, all the way to the most distant galaxies we can see! Many, though maybe not all, of these new stars also will have planetary systems. Our best guess right now is that at least 5% of stars have planets around them. Given that there are over 10 billion stars in the Milky Way, this means that there are at least 500 million planetary systems in our galaxy. And there are millions upon millions of galaxies in the Universe!

The harder question is, how many of those planets are capable of supporting life? The answer is: we don't know. We have no clue. In our Solar System, one of the eight (or nine) planets certainly has life, maybe Mars does or did, too. So maybe you could guess that one out of 10 planets in our Galaxy can host life. But we don't know how many planets there are in other solar systems. We can only detect Jupiter-sized planets or larger; these probably can't have life. But their moons may be able to.

Many other solar systems have giant planets very close to their sun; ours doesn't. In some of the other Solar Systems, planets have very oval orbits, meaning sometimes they are very close to their parent star, sometimes they are far away. In our Solar System, the orbits are pretty close to circles. This is good for life, because our temperature doesn't change drastically. Imagine if the Earth got as close to the sun as Mercury and as far away as Jupiter. At some parts of our year, the rocks under our feet would melt! At other parts of the year, the oceans and parts of our atmosphere would freeze solid. That would be bad.

NASA is working on a space mission to count how many Earth-sized planets there are in Earth-sized orbits around other stars. The Kepler Mission is very ambitious, and we don't know what we will find. Other astronomers are working on possible ways to detect life on those planets, maybe by looking for ozone or chlorophyll or other compounds that life creates.

Maybe in 10 or 20 years we can start to have a better guess as to how many planets there are capable of harboring life. But for right now, we only know of one. Maybe there are billions, maybe just one. In the meantime, we can focus on making sure the one we know about stays a good place for things to live. There may be no where else to go!

Tuesday, January 30, 2007

Curses! Foiled again.

If you remember from a the few posts ago, I spent much of the past 2 weeks writing proposals to use the Hubble Space Telescope. So, you can imagine the foul mood I was in yesterday when NASA announced that Hubble's main camera quit working Saturday morning, only 11 hours and 26 minutes after the deadline on proposals. And, of course, this is the camera I was proposing to use in my work.

The camera is almost fully dead due to problems with the electronics. It may (or may not) be possible to fix it when astronauts come to repair the Hubble in about 18 months, but they have a long list of things to do already, and the astronauts will be installing a camera that is almost as good as the dead camera in some respects, and better than the dead camera in other respects.

The camera that died, the Advanced Camera for Surveys (ACS), was truly the workhorse instrument of Hubble. At the end of the day on Friday, there were 747 proposals to use the Hubble over the next year; 498 of those were to use ACS.

NASA has decided to re-open the system to proposals in order to try and fill the gap left by the loss of ACS. I might be able to change my proposal to use another, older camera that isn't as powerful as ACS. It has a smaller field of view, and is much less efficient at detecting light. But, given the choice between that and none, I'll take the older camera.

Monday, January 29, 2007

Sad rememberances

This week represents one of the tougher weeks that NASA has ever had. NASA's worst three disasters all happened in a six day span (though spread out over 36 years).

On the late afternoon of January 27, 1967, Gus Grissom, Ed White, and Roger Chaffee, the crew of Apollo 1, were running a full scale test of the first Apollo capsule in preparation for a launch sometime that spring. To simulate a launch realistically, the cabin was filled with pure oxygen and pressurized. That evening, as the test was winding down, a spark caused by a short in the wiring occurred, and a fire was started. Since the atmosphere was complete oxygen, the fire was basically an explosion. Opening the door from the inside required the astronauts to remove 12 bolts and to pull the door inwards against the pressure of the interior air. The astronauts had no chance to escape and were killed by smoke inhalation within 20 seconds of the spark.

The day of January 28, 1986 was a snow day for my school in southeastern Pennsylvania. I forgot that the shuttle was supposed to launch that morning (in 6th grade I already loved space), so I was sledding in the backyard when I heard the phone ring. It was my mom, calling from work, to say she heard something about the shuttle landing in the Atlantic Ocean. Being a space nerd, I knew that the shuttle had plans to ditch in the ocean if something bad happened at launch, so I guessed (wrongly) that had happened. I went and turned on the TV to find out that, horribly, the shuttle Challenger had exploded during liftoff.

That morning had also been a cold one in Florida. Ice had formed around the launch pad; no shuttle had been launched in such cold weather. But the launch was to go on. Two previous launch attempts had been scrubbed, and this was a high-profile mission, as teacher ChristaMcAuliffe was on board and would be broadcasting her spaceflight to schools across the country. But the cold weather doomed the space shuttle. In the cold weather, the rubber that made up the seals between parts of the Solid Rocket Boosters became less pliable, and one of the O-rings failed to seal. Hot rocket gas escaped from the side of one of the boosters, eventually causing the external fuel tank to fail, which led todisintegration of the entire vehicle. All seven astronauts, Michael J. Smith, Dick Scobee, Ronald McNair, Ellison Onizuka, Christa McAuliffe, Gregory Jarvis, and Judith Resnik, lost their lives.

On February 1, 2003, I had just arrived in Tucson, Arizona to start a new job as a postdoctoral researcher there. I was temporarily renting a room in a graduate student's house while I waited for my own apartment to become free. I was going through my normal morning routine and turned on the TV to get the news. The story was alarming -- the Space Shuttle Columbia, returning from a two week mission, was "late" in showing up at Kennedy Space Center.

I knew this was disastrous. Space shuttles cannot be late -- once the rockets fire to bring it back in to the atmosphere, Sir Isaac Newton's gravity takes over. The shuttle's engines cannot fire during re-entry, so it cannot "circle" if there is bad weather or other problems. The fact that it was "late" meant that it was, in reality, lost.

The shuttle Columbia, unbeknownst to anybody, had a hole punctured in its wing during takeoff. During re-entry, super-hot gases (the same gases that burn up meteors) surround the spacecraft. The tiles on the out side of the shuttle protect it from that heat. (I remember seeing an episode of the Today show on a launch day many many years ago, and BryantGumbal was holding, in his bare hands, a shuttle tile that was glowing red-hot and being heated with a blowtorch.) Without protection from the hot gases, the metal on the interior of the wing melted, allowing even more gas in. Eventually the wing failed, and the shuttle tumbled out of control and disintigrated. Rick Husband, William McCool, Michael Anderson, David Brown, Kalpana Chawla, Laurel Clark, and Ilan Ramon, the seven crew members, were lost.

Space flight is dangerous. Human beings are not designed for space. So while it is very sad that these 17 astronauts (plus at least another four Russian cosmonauts, and many more from around the world killed in training accidents) died in space, they knew the dangers they were facing.

But the saddest part is that all of these three accidents were preventable. Before each accident, some people were worried about the root causes. And while we must remember that hindsight is always perfect, and remember that somebody is always worrying about something, and remember that we can never make spaceflight 100% safe, we must seek out the human failures that led to these disasters. We must make whatever cultural changes need to be made to prevent those human failures from causing any more deaths.

Sad to say, we will lose more people in space, someday. As private industry begins to send people into space, some of those will be killed, too. So now is the time for each of you to ask yourselves, what is an acceptable limit on losses? For what are we asking astronauts to risk their lives? How much risk should we allow private citizens who pay to go into space to be placed in?

These are questions that I cannot answer, because each person will have a different opinion. Over time, spaceflight will get safer and more reliable. We've seen this happen with airplanes. With boats. With cars. But also, we cannot be negligent and allow people to put their lives and those of others in needless risk. Having such discussions now, and not after the next disaster, should be the legacy of this week, of those we lost in our first tentative steps into the cosmos.

To read NASA administrator Michael Griffen's remarks on NASA's Day ofRemembrance, click here.

Friday, January 26, 2007

Proposing to use telescopes

Whew! I have worked harder this week than for a long time, all trying to get some different proposals to use the Hubble Space Telescope done. I sent one in a few minutes ago, and other collaborators at other institutions are putting finishing touches on others, so I can finally relax.

Many of you probably are wondering, "What the heck is this proposal he's talking about, anyway?" So let me explain.

The vast majority of professional astronomers do not work in front of a telescope. We spend most of our time in an office in front of a computer to do our work. Professional astronomers share all of our large telescopes with other astronomers at our institutions, at other schools, and around the world. So if I learn of a neat object I want to study, I can't just jump in my car, drive to the mountain top, open up the dome and start looking. Somebody else is probably already using the telescope, and they won't be too happy if I force my way in to the dome and try to take over for the night.

In order to get the telescope, I must start by writing a proposal. A proposal has two jobs. First, I have to show that the science I want to do is interesting. If I say I want to see what phase the moon is, people will say that is boring and stupid, and they won't waste time on my project. But if I say I want to look for new moons around Pluto because any such moons would help to tell us how Pluto formed, then people might start to think it was interesting.

Second, I have to prove that my project is suited to the telescope I am asking to use. If I try to take a picture of Venus with the Keck 10-meter-wide telescope in Hawaii, there will be so much light I will hurt the cameras, which will make a lot of people mad. Likewise, if I say I want to take a detailed look at super faint galaxies with a tiny telescope, I won't get anything useful, because small telescopes can't see really faint things.

So, observatories ask for proposals to use their telescopes one to four times a year. A group will then get together to evaluate the proposals. Is the science worthwhile? Is the telescope the right one for the job? If so, they'll put me in a schedule to use the telescope. If not, then they'll say "sorry, better luck next time," and I won't get to use the telescope.

As you can guess, being able to write a good proposal is an important skill for astronomers. I've spent several days (most of the last week and many partial days over the past month) working on my proposals to use the Hubble Space Telescope. But my proposal only has about 5 pages of text, plus a couple of graphs. They won't take anything longer, or else the committee that assigns time will have to sift through tens of thousands of pages, as there are often more than 1000 proposals to use the Hubble! That's a lot of reading.

For fun, I'm putting a PDF version an old proposal from 2004. The project got time on the Keck Telescope that fall. You can try and read it if you want, though I will warn you it is technical and quite boring. And you will find a few grammatical mistakes, typos, and stylistic problems. It's amazing how much of that can sneak through even though you've been staring at the same 5 pages for days.

And to those who have sent me emails in the last month, I will get around to answering them now that I am both home and finished with deadlines. I'm sorry it is taking so long.

Tuesday, January 23, 2007

busy busy busy!

Sorry to not have much to say for the past few days. At the end of this week, proposals to use the Hubble Space Telescope are due, and I'm trying to catch up on things after a month on the road. I'll be back soon!

Saturday, January 20, 2007

The agony and the ecstacy of science

In 1911, Norwegian Roald Amundsen and Englishman Robert Scott were in a race across Antarctica to reach the South Pole. Scott and his party braved pack ice, storms, and fierce cold to reach the South Pole, only to find that Amundsen's team had arrived a month earlier. Sadly, Scott's expedition perished just miles from food and shelter as they attempted to return home.

In a much, much less serious situation, I had a somewhat similar polar experience last night. I am using the Keck Observatory to identify the types of stars in the open star cluster Messier 67 using a spectrograph (see my article on spectra to see how we can learn about stars these spectra). Anyway, one of the spectra was very weird -- it had bright lines, dark bands, and was, for lack of a scientific term, very funky. After puzzling for a while, I figured out that the object was a "polar" (pronounced "POLE-are") -- a white dwarf star with a very strong magnetic field that is pulling material away from a neighboring star.

This was exciting -- I didn't know of any polars in star clusters, so this was a potentially important discovery. So, I put the coordinates of the star into a star database to see if the star was known. I was certain it was unknown, as this star was very faint. BUT, there it was in the catalog, having been discovered 15 years ago and observed a handful of times since then.

Very quickly, a lot of the excitement drained from me, and I was tired. Not surprising, since it was 4am. But my important discovery was gone. I DO have some of the best data ever taken for this object, and there is a lot of science we can do with this information.

One common theme in science is that many things are "discovered" several times. But, thanks to the power of libraries and computer searching, I can't take credit for re-discovering this star. But, I am keeping my eyes peeled for another interesting star that everyone else has overlooked!

Friday, January 19, 2007

Playing with the world's largest telescope

Tonight I have the honor of using one of the two largest telescopes in the world at the Keck Observatory on Mauna Kea in Hawaii.

If you've been reading my blog for a while, you know that these telescopes were damaged by two major earthquakes just a couple of months ago. Other than the telescope moving a little slower than specs and a few missing ceiling tiles here and there, everything seems to be back to normal.

We are searching for white dwarfs, the slowly fading ashes of stars that have used their nuclear fuel, in some star clusters. The star clusters are easily visible with binoculars or small telescopes, but we need a telescope nearly 33 feet across in order to get a good view of these very faint stars.

I need to keep tending my telescope, so I'm off. But, if you haven't yet taken part in my readership poll, please do. I'd like to get to know you all better, and these statistics help! Thanks for your time!

Thursday, January 18, 2007

The Great Comet of 2007

Many of you (myself included) have likely missed one of the celestial shows of the decade. Comet McNaught, shown above in a picture taken by Andrew Drawneek in New Zealand and published on Sky Tonight's webpage, has become the brightest comet in decades. Due to some bad geometry it was hard to see in the northern hemisphere, and now it has moved so that it can only be seen well south of the equator. I tried to see the comet a few times, but the weather was typically bad.

Why did this comet get so bright so fast? Comet brightnesses are hard to predict. Some comets put out a lot of dust, others put out more gas (like water vapor and ammonia). Dust readily reflects sunlight, so dusty comets are brighter. Distance also plays a role in how bright a comet appears. Comet McNaught came about 76 million miles of the Earth, while Hale-Bopp (the bright comet in 1997) never came closer than 122 million miles. In 1996, Comet Hayakutake became very bright as it passed within 10 million miles of the Earth; had it been at Hale-Bopp's distance, it would have been invisible to the unaided eye.

Comet McNaught has one unique property for a comet -- its orbit. Most comet orbits are very elongated ellipses (ovals) that take the comet tens of billions of miles away from the sun, and then bring it back to within a few tens of millions of miles. But Comet McNaught's orbit seems to be a hyperbola, meaning that it may completely escape from our solar system, never to return. Jupiter is probably responsible for this travesty -- its gravity can give a comet a little extra energy and kick it out of the solar system completely.

For a real treat, check out the videos of the comet on this SOHO Spacecraft website. The SOHO spacecraft constantly watches the sun. In the movie, you see the comet come in so bright that it nearly blinds the camera. The comet passes the planet Mercury (the bright star in the lower left) and slips out the other side of the camera. The disk that you see in the middle blocks the sun's light; the little white circle shows you the actual size of the sun. The blue color is not real -- this is really a black and white image.

Tuesday, January 16, 2007

The passing of a great astronomer

I was concocting a thrilling tale to tell you all about dodging ice storms which would lead in to the comet now visible in broad daylight, when I was startled to receive news about the death of Don Osterbrock, a retired professor of astronomy at Lick Observatory in Santa Cruz, California.

I won't try and write obituaries, as two online (from UC Santa Cruz and Sky & Telescope magazine) are more than adequate. But I will talk a bit about Don and my interactions with him.

Although Don Osterbrock didn't win a Nobel Prize (he won almost every other award an astronomer can get, though), he was a household name among astronomers. He wrote a textbook on nebulae and active galaxies that almost every astronomer learns from at some point. He was director of Lick Observatory for many years. He was passionate about his work and astronomy (as anybody who ever made him angry can attest to). And he continued working for 15 years after his retirement, right up to the day he died.

I met Don when I arrived at UC Santa Cruz in 1997, but I got to know him much better when I moved into a grad student office right next to his office in 1999. I helped Don quite often with his computer. He used it mainly for email, and he didn't really care to use it for much more than that. Sometimes the computer would forget itself or he would need to print out an email, and he'd track me down to help. Don also was one of the few faculty members who came to listen to my thesis defense in 2002, and in my visits back to Santa Cruz since then he seemed genuinely happy to see me. Now I wish I'd stopped by more often.

Don was also known for traits that few astronomers had. When deadlines for titles of talks to be given at our annual astronomical meetings were announced, there was special recognition for those who beat Osterbrock; usually only a few people received that recognition. The rest of us were happy to get our titles in be the deadline, weeks later. Don often gave lunchtime talks at Santa Cruz about personalities in the history of Lick Observatory. Often the talks were a little dull, but buried in a slew of old pictures were anecdotes that brought the names to life. Anybody who thinks that scientists are passive people who operate only on pure reason need only read some of Don's work to see that passion and emotion often play large roles in the lives of scientists.

My thoughts are with Don's widow, Irene, a wonderful lady who I only met a few times when she would stop by for lunch or on her way home.

Friday, January 12, 2007

More reader mail: how long it takes stars to cool down

I'm in the middle of my third business trip of the year. This morning, I found I'm already 15% of the way to achieving platinum status on American Airlines for 2007 (that takes 50,000 miles traveled). Fun! At any rate, I probably won't be able to blog again until late Tuesday.

Today, I'll answer another question I received by email from a reader. Bret asks, "How long does it take a neutron star to cool off to the temperature of its surroundings?"

This is a good question, and unfortunately we don't know the answer all that well. But let's start by reviewing what a neutron star is, for those who may not know.

A neutron star is the remnant of a star that was about 8 or more times the mass of the sun. When such a massive star has used up all of its fuel (in just a few million years, as opposed to the sun, which will last for 10 billion years), it has a core made out of iron. Stars get their energy from nuclear fusion, but iron does not make energy in nuclear reactions. So, the iron core just sits there and grows. When it gets large enough (about one and a half times the mass of the sun), the iron can no longer stand up to the crushing pull of gravity. Electrons merge with the atomic nuclei to make a neutron star (essentially a giant atomic nucleus!), and the rest of the star explodes as a supernova.

A neutron star is about 1.5 times more massive than the sun, but is only about 10 or 15 miles across. Think about shrinking the sun until it was the size of Manhattan! Now, the neutron star begins its life with temperatures of a few million degrees on its surface (and over a billion degrees in its center!). When young, the neutron star has a very strong magnetic field, and the star loses energy through this magnetic field, as well as through invisible, nearly-massless particles called neutrinos.

After about a million years, the outer temperature of the neutron star has dropped to a few tens of thousands of degrees. Sometime around this point, the magnetic field begins to break down and the star stops producing neutrinos, and the neutron star will cool in a "normal" way -- by emitting photons. This is how hot things cool in our everyday life, by radiating away energy.

The time it takes a neutron star to cool to the temperatures of interstellar space is uncertain, but likely to be much longer (billions of years). The time depends on the amount of heat energy in the material (its heat capacity) and the rate at which the star loses that heat through radiation. In an ideal world, that rate of radiation is faster for higher temperatures and faster for objects with larger diameters. So, as a neutron star gets closer and closer to the ambient temperature of space (only a few degrees above absolute zero), it wil cool more and more slowly.

One problem is that we don't know how much heat the neutron star can hold, because we don't know what they look like on the inside. It is not possible to replicate the conditions of a neutron star on the earth, so there are many theories, including "soft" and "hard" equations of state, and quark and strange matter varsions of neutron stars. I won't try to explain these differences, as I don't understand them well myself.

In fact, one way of testing theories about the structure of neutron stars is to compare their observed cooling rates with those predicted by different theories. This work is just beginning, though, so it will likely be a long time before we understand neutron stars!

Thursday, January 11, 2007

The singular nature of black holes

Black holes are one of those objects that every member of the public seems to be interested in, and rightly so! Lots of weird things happen around black holes, and they are so hard to study that there are lots of theories as to what happens in and around black holes.

Several days ago I got an email question from Mike in Maryland about black holes. I'll paraphrase the question:

Different astronomy books, both at the general public level and the college textbook level, describe black holes differently. Some say it has a certain radius, and some say a black hole is a singularity (an infinitely dense, infinitely small point). Which is it?

This is a very good question, and the answer is both simple yet very subtle ("subtle" is astronomer speak for "complex and something we don't really understand, so we sweep the details under the rug"). The simple part of the answer is that the two descriptions of black holes are talking about two different parts of the black hole: the event horizon and the material in the black hole itself.

The event horizon is the smallest part of the black hole we could ever hope to see. At the event horizon, the "escape velocity," or the speed at which something needs to move to escape the black hole, is the speed of light. Since nothing that we know of can go faster than the speed of light, anything that gets inside the event horizon stays there. Another way of thinking about it is that anything that happens inside the event horizon is invisible to the rest of the Universe.

The size of the event horizon depends on whether the black hole is spinning (most probably are), but is around 6 km (about 3.5 miles) across for every solar mass of material in the black hole. In other words, if we wanted to turn the sun into a black hole, we'd have to squeeze all of its matter into a ball less than 6 km across. Black holes that form from the explosions of big stars are between about 3 and 100 times the mass of the sun, and so their event horizons are 18 to 600 km (about 10 to 375 miles) in diameter. The black hole at the center of the Milky Way galaxy is thought to be about 6 million times the mass of the sun, so its event horizon is about 36 million kilometers, or 22 million miles, in diameter. If we were to put this black hole in the center of our solar system, it would easily fit inside the orbit of Mercury!

Since we can never see what happens inside of a black hole's event horizon, most astronomers are happy to say a black hole is 6km is diameter per solar mass. But this doesn't tell the full story. What happens to matter that falls inside the event horizon?

At present, we don't know of any physical force that can stop the collapse of material inside of a black hole. So, it is theorized that material is squeezed into an infinitely dense, infinitely small point at the center of the black hole. This is called a singularity. But singularities are nasty things. Mathematically they are okay, but in the real world, we never see things go to infinity. Some process always tends to show up that keeps things from going to infinity. In the case of black holes, that process may be quantum mechanics.

Quantum mechanics seems to be the process that rules things at atomic sizes. In quantum mechanics, the smallest size that you can talk about is called the "Plank length." The plank length is extremely small -- If a yardstick (meterstick) were the size of the Universe, then the Plank length would be many times smaller than a single atom. Despite being so incredibly tiny, the Plank length is still a far cry from being "infinitely small." So, many physicists suspect that a true singularity could never be smaller than the Plank length.

General Relativity, Einstein's theory that seems to describe gravity in the Universe, and the theory that astronomers use to describe black holes, does not include quantum mechanics. So, many physicists think that Einstein's theory cannot hold once you get down to the sizes of atoms. Many physicists are working on a quantum theory of gravity, but this is proving extremely difficult to work out. Given all of this, I think most astronomers would admit that we don't know what happens inside of a black hole's event horizon. Maybe there is a singularity down in there. Maybe there is a new form of matter that we don't know about, and stuff that falls into the black hole is transformed into this new matter. Or maybe space and time itself rip, and the material that falls in a black hole is transported somewhere else in our Universe or into another Universe. Or maybe the giant robot Maximillian is collecting matter to try and take over the Universe. We just don't know.

To summarize all of this, the answer to the above question is that a black hole's event horizon has a known size, about six kilometers in diameter for every solar mass of material in the black hole. But the size and makeup of the lump of matter inside a black hole is completely unknown at this point.

Wednesday, January 10, 2007

Take the poll!

As part of my desire to learn a bit about you all and to better serve my readership, I've made a poll of some basic questions. If you would be so kind as to take a few minutes to answer these questions, I would greatly appreciate it!

You can access the polls by clicking on "Polls" on the menu to the left. Know that I take your personal privacy very seriously, and there is no way for me to track who gave what answers to the polls. And I never would give any information to third parties. Click on "Privacy" to view my privacy policy.

I'm still learning how to incorporate the polls into my web pages, so I apologize for some little quirks (like the layout).

Exciting times at Kitt Peak!

First, a thank you to several people who have sent emails and comments in the past few days. I will get around to answering them, but it may take a while. I was traveling by plane again today, and am working at Kitt Peak with two grad students from the University of Texas, pictured above. Between the three of us, we had managed to grab a total of 8 hours of sleep last night. So, earlier while I worked on solving some computer problems, they grabbed a quick nap.

Those of you who have a crystal clear view of the western horizon at sunset in the next couple of days should try to look for Comet McNaught about 20 minutes after sunset. Although the sky will still be bright, you may have a chance at spotting one of the brightest comets in years. In the next couple of weeks, Comet McNaught may be as bright as the planet Venus, but it will be between the Earth and the Sun and so invisible if you are not a spacecraft. I looked from here tonight, but distant clouds blocked my view of the horizon.

Sunday, January 07, 2007

Shakespeare and the Second Law of Thermodynamics

"A good many times I have been present at gatherings of people who, by the standards of the traditional culture, are thought highly educated and who have with considerable gusto been expressing their incredulity of scientists. Once or twice I have been provoked and have asked the company how many of them could describe the Second Law of Thermodynamics. The response was cold: it was also negative. Yet I was asking something which is the scientific equivalent of: Have you read a work of Shakespeare's?

"I now believe that if I had asked an even simpler question -- such as, What do you mean by mass, or acceleration, which is the scientific equivalent of saying, Can you read? -- not more than one in ten of the highly educated would have felt that I was speaking the same language. So the great edifice of modern physics goes up, and the majority of the cleverest people in the western world have about as much insight into it as their neolithic ancestors would have had."

-- C. P. Snow, The Two Cultures and the Scientific Revolution

The above quote was mentioned by a speaker, Jay M. Pasachoff, during the conference I've been at the last two days. A large part of our meeting was devoted to discussing not only science, but the role of the scientist in educating the public about it.

I have not read the whole of C. P. Snow's essay, but I find the above excerpt provocative. I will not try and discuss what little I know of the controversy behind the essay, nor can I agree with the points made in this excerpt, but I can say there is a valid point to be made.

Modern society claims to value science. After all, science has brought us medications that have extended our lives and technologies that have improved the quality of life. Yet much of the public understands very little about scientific fundamentals. Most of the people in this country cannot correctly explain why the Earth has seasons, what DNA is, or what determines whether an atom is gold or uranium, or the difference between an organic and an inorganic compound. Yet these concepts are not details, they are fundamentals. Yet most people could tell the difference between prose and poetry, and most people have a rough idea how our government works, and most people know the difference between music and sculpture. If we couldn't do these last three things, much of society would be very worried. Yet if we can't talk about the basics of science, most of society is not worried.

A lack of science knowledge hurts people. Misunderstandings about medical research result in people getting scammed out of billions of dollars with the latest miracle cure. In the winter, people are hurt in needless automobile accidents because of freezing rain, because the drivers don't realize that liquid rain can freeze when the temperature is below freezing. People are killed when they mix bleach with ammonia-based household cleaners. Many of these could be avoided with a minimal knowledge of science.

So, why does society tolerate ignorance of science? I don't know. I can make some guesses. A lot of the details of science require understanding and ability in abstract concepts and mathematics. But this doesn't mean that you need to be able to do multi-variate calculus to get some scientific concepts. Calculating how fast fish accumulate man-made toxins is a difficult scientific endeavor, but a little bit of scientific knowledge lets most people realize that dumping leftover pesticide in the stream that leads to your favorite fishing hole is not a smart idea.

At any rate, I don't want to preach. You who are reading this blog are already making an effort to cross this societal divide, and I will make the effort to reach out the other direction. You can rest easy that I will never ask you to tell me how long it takes a neutron star to be disrupted by a rapidly-rotating black hole. That would be like me asking you for proof that "The Magic Flute" and "The Marriage of Figaro" were both composed by the same person. We'll leave those details to the specialists. But I hope that I can help to enhance your knowledge of science and astronomy in ways that help to integrate science into society instead of widening the chasm.

Saturday, January 06, 2007

Meeting with fellow Fellows

As promised, I am in Seattle for a meeting of the National Science Foundation Astronomy & Astrophysics Postdoctoral Fellows (we just say AAPF for short). Above is a picture of our merry band. I asked them to smile and wave, but you can see the half-hearted effort.

The meeting has several aspects. We have a few keynote speakers talking about their experience in research and education, including Prof. Jay Pasachoff of Williams College talking about his work on understanding how the sun works and his work with teaching astronomy, from building his own telescope in the Bronx to chasing total eclipses of the sun in the Mediterranean and Siberia. We had a panel discussion about searching for jobs in astronomy, and we had talks by the fellows (including yours truly) about our research work.

I often say that the worst weather is 40 degrees and raining, and today reaffirmed that belief. It was 40 degrees, raining quite hard, the wind was blowing, and we had to walk several blocks to dinner. The damp air just cuts through clothing in a way that colder but drier air cannot. I hope tomorrow is a little less raw, but I think it will be more of the same.

Thursday, January 04, 2007

Are you on MySpace?

As part of my efforts to increase the audience of my website and blog, I've established a toehold on MySpace. I don't do much there -- I've put up a java headline ticker for the blog, put up a couple of pictures, and add people to my friend's list. So, if you don't know what MySpace is or don't have a site there yet, there's no need to rush over and sign up for fear you will miss some exciting astronomical tidbit.

But if you are online at MySpace, feel free to look me up, add me as a friend, whatever. My MySpace site is: (isn't THAT a shock?).

Heading off to sunny Seattle

Okay, it's probably not sunny in Seattle. If you really want to know, take a look at the Space Needle Webcam for a live shot. Looks kinda wet right now. No wonder coffee was invented in Seattle (or something like that).

But, later today I am off to Seattle anyway. Starting Sunday is the 209th meeting of the American Astronomical Society, which meats twice a year. The winter meeting is the biggie, with several thousand astronomers from across the continent arriving to talk about their work. If you live in Seattle, happen to be passing the Convention Center and hear people in a heated discussion over the value of "w," know that they are likely astronomers, so please don't call the cops on them.

This also means that you are likely to see a flurry of news reports about new astronomical findings. If you see something that I don't mention and you want to ask about, please drop me a line! Links to online news articles are helpful, too, because the press often completely garbles the results, but with the full story, I can often piece things back together.

I am headed out to the meeting early because there is a meeting of the other astronomers in the country who have the same fellowship I have, the National Science Foundation's Astronomy and Astrophysics Postdoctoral Fellowship. We have a day and a half of meetings planned, both to introduce ourselves to each other, to talk about each other's research, and to participate in that all-important job of networking. I'm guessing that there will be about 20 fellows there, plus a handful of invited guests.

I'll will bring you news as it unfolds!

Tuesday, January 02, 2007

New Year's Resolutions

Yesterday, the first of January 2007, at almost 12 noon Greenwich Mean Time, the Earth finished another orbit around the sun. "But wait!" you cry. "Shouldn't that be midnight?"

Our calendar places the new year at midnight local time, yes. But the Earth doesn't take exactly 365 days to circle the sun. It takes almost 6 hours longer than that (More precisely, it takes 365 days, 5 hours, 48 minutes, 45.216 seconds to complete a tropical year, but let's not get too picky.) And since this is the second New Year's Day since the last Leap Day, then that adds up to about 12 extra hours. We'll get rid of those extra hours on February 29, 2008.

But no matter when you shouted, "Happy New Year!" I wish you best wishes for the coming year, however you define your year.

Over the holidays, I was visiting much of my family across the United States. And they reminded me how little most people know about the job of an astronomer. This is not because most people are stupid or ignorant or anything like that; it is because the job of the astronomer is different from what most people expect or would guess. My goal with this blog is to illuminate the job of the astronomer and to teach you a little about astronomy and modern science along the way.

If you ever have any questions about anything I post here, if you are uncertain about anything I've written, or if you have any questions about anything, feel free to leave a comment or send me an email. I'll probably respond, though it can take me a while. Remember, there are no stupid questions! (I wish could promise there would be no stupid answers, but if I'm running low on coffee, or running short on sleep, or my brain has decided to disengage from reality, stupid answers are sometimes the result.)

Happy New Year!